Examine glial cells and other types of neurons in a section of the cerebellum (slide 71 or 148). Using Fig. 9-6 as a guide, look for

• Neurons of the molecular layer,
• The granular layer, and
• The very large Purkinje cells (a type of neuron) at the boundary between these layers.

Also on slide 71, examine the distinctive choroid plexus (Fig. 9-20), with epithelial cells covering a mass of capillaries and pia mater.

What is the function of the choroid plexus?

Examine a section of spinal cord (slides 9, 149). The tissue is somewhat disrupted, but identify the central gray matter, containing motor neurons, “interneurons”, the central canal lined by ependymal cells (Fig. 9-12), and the outer white matter, consisting largely of myelinated fiber tracts (Fig. 9-14).

Where are most of the neurons and what is the major glial cell of white matter?

Clinical note: The CNS is subject to various diseases in which there is destruction of the myelin sheaths, such as multiple sclerosis (MS). The functions and body regions affected by MS depend on where in the CNS the focal areas of demyelination occur. Weakness and paralysis of one or more limbs are common sequelae of this disease.

Now for ganglia.